Penta AQ170 engine swap

[Mbaumann]

I’m having some plans to replace my current 120bhp B30a engine with the 170bhp Penta AQ170 engine.

I would therefore like to hear if others have made the same engine change or if people have something that says it is a bad idea.

 

No, I don't want to get a diesel engine.

 

Please come with your thoughts and ideas.

[eile]

Same engine but diffrent camshaft and intake.   If it has been used in a boat they had some cooling problem (what I heard) and if it has gone with seawatercooling it could be lots of rost. 

[Frippe S]

From what I remember most of the power was limited to a narrow and quite high rpm span

 

[Tamaz]

My thoughts were like Frippes, in a boat you can optimize for a specific RPM, match "gearing" (with the prop size and angles) to run in that RPM-sweetspot almost all the time. A car would need power in a bigger range, and a TGB especcially would need some at low RPM to handle offrading at low speeds.

Having more consistant power over a bigger range of RPM usually cuts of the spike, bringing the "max hp" down a bit. Just looking at a top HP number does not say much about the engine caracteristics.

I'm not saying it has to be a bad idea, just get some propper info of the engine caracteristics. Best would be a HP/Torque graph over the whole RPM range.

TL:DR
You need more information on the engine specs before moving on. Getting 50 more HP is not gonna do you any good in a TGB if that extra power comes at say 4-5000 RPM. Even more so, getting to that extra power at high RPM probably traded of some at lower RPM, and worst case you actually get less power in the range most used in a TGB.

[Mbaumann]

Thank you guys. 
You have given me something to think about before jumping in to the project for more power without changing to a diesel